Blue Feces

… In general, if two individuals track the same external properties (chemical properties, bodily disturbances, shapes), but undergo radically different internal processing (across-fiber patterns, somatosensory firing rates, shape processing), and exhibit radically different affective and sorting behavior, then arguably things experientially seem different to them. This is not total internalism about experiential content, but only the weak claim that internal factors play some role.

“Hydrogen cyanide (HCN), also known as hydrocyanic acid, prussic acid or Blausäure was the toxic agent in Zyklon-B. Strictly speaking, the term hydrogen cyanide should be used for the pure compound and the term hydrocyanic acid reserved for its aqueous solutions, but this convention has been ignored so much that it is pointless to insist upon it. HCN is a high vapor pressure liquid; the Merck index lists its boiling point as 25.6 degrees Celsius (78.8 degrees Fahrenheit), significantly less than human body temperature. At room temperature (25 d C, 77 d F) the equilibrium vapor pressure of HCN is 750 Torr (760 Torr = 1 atmosphere), corresponding to 987,000 ppm. At 0 C (32 F) it is 260 Torr corresponding to 342,000 ppm. The Merck index warns, “Exposure to 150 ppm for 1/2 to 1 hr may endanger life. Death may result from a few min exposure to 300 ppm.” Clearly, it is not necessary to reach equilibrium vapor pressure in order for the fumes of the liquid to be quite deadly.

[ ... ]

[Fred A.] Leuchter’s primary mistake is his initial assumption that exposure to HCN must result in the formation of Prussian blue. Another error is his claim that the delousing facilities were exposed to less HCN than the homicidal chambers. It turns out that it is more difficult to kill lice than it is to kill humans.”
– Richard J. Green, The Chemistry of Auschwitz

The first quote, above is from a review of the book, The Red and the Real: An Essay on Color Ontology by Jonathan Cohen; reviewed by Adam Pautz in Notre Dame Philosophical Reviews. The second quote (about hydrogen cyanide) is found within an essay, Thirty-Six Shades of Prussian Blue by Joshua Cohen; from TripleCanopy. First below is more from the Red and Real book:

…On a natural account of interspecies variation (e. g. between a human and a UV-sensitive pigeon), different species track and thereby perceive overlapping but distinct chromatic properties of the same objects. On the present account, something similar applies to intraspecies cases like that of John and Jane, only it is more subtle

… Maxwell is an actual person and Twin Maxwell is a hypothetical individual who occupies a possible world in which the evolution of color vision proceeded somewhat differently than in the actual world. Alternatively, Maxwell and Twin Maxwell might be supposed to belong to distinct but similar species in the same world. They are exactly alike at the receptoral level. Indeed, by stipulation, when they view the same object, x, they stand in the optimal tracking relation to the very same non-relational chromatic property of x: there is not just overlap but complete identity in what they optimally track. But, the case continues, they differ radically in postreceptoral “opponent” processing and color-related sorting and discriminatory behavior. In fact, we might suppose they differ in these respects more radically than John and Jane do. This is a theory-neutral description of the case.

Cohen argues that Maxwell and Twin Maxwell would represent x as having different colors, for instance unitary blue and orange. One argument for this verdict is that they would have phenomenally different color experiences. And, as Cohen argues, if two individuals have different color experiences, and the difference is not due to a difference in illumination, then nothing could be more natural than to say things look different in color to them. (Indeed, although Cohen himself remains neutral on whether there would be an experiential difference in the Maxwell-Twin Maxwell case, it seems to me that there would be a representational difference only if there would be an experiential difference.) This verdict is bolstered by consideration of other cases. In general, if two individuals track the same external properties (chemical properties, bodily disturbances, shapes), but undergo radically different internal processing (across-fiber patterns, somatosensory firing rates, shape processing), and exhibit radically different affective and sorting behavior, then arguably things experientially seem different to them. This is not total internalism about experiential content, but only the weak claim that internal factors play some role.

And now back to the Prussian Blue essay — which is almost entirely a collection of quotes (a “writer” after my own heart!):

Dry thoroughly in an iron vessel and powder grossly, any quantity of fresh blood. Dry thoroughly and powder also a quantity of pearl ash equal to the powdered blood. Mix them, and calcine them in a low red heat in a crucible with a loose cover until all smoke and flame ceases: then make the cover fit close, and calcine in a full red or nearly white heat for half an hour. The crucible should not be more than two thirds full, as the mixture is apt to swell. Empty the contents of the crucible into warm water in the proportion of a quart to four oz. of the mixture. Pour on again as much warm water: mix and filter the solutions. Dissolve of sulphat of iron (green vitriol) and of alum, of each a quantity equal to one half of the pearl ash employed. Pour the solution of alum and green vitriol mixt together, gradually into the solution of blood and alkali: both solutions are better for being warm, but not boiling hot. Stir it well. Let the sediment settle. It will be of a dirty greenish colour: wash it. Then digest it for 2 or 3 days in diluted muriatic acid (spirit of salt one part, water two parts). The colour by this means gradually becomes blue, because the muriatic acid dissolves the yellow oxyd of iron which is not combined with the prussic acid. Wash it repeatedly. Dry it on chalk stones, paper, linen, or any other mode of draining off the water. Spread it thin to expose it to the air. I have kept the lixivium of blood and alkali (prussiat of potash) for a year and a half in bottles, and used it to make prussian blue with equal success as at first. Chippings of hoofs answer equally well with blood.
– John Redman Coxe and Thomas Cooper
The Emporium of Arts and Sciences

Paper simply washed with a solution of this salt is highly sensitive to the action of light. Prussian blue is deposited (the base being necessarily supplied by the destruction of one portion of the acid, and the acid by decomposition of another). After half an hour or an hour’s exposure to sunshine, a very beautiful negative photograph is the result, to fix which, all that is necessary is to soak it in water in which a little sulphate of soda is dissolved, to insure the fixity of the Prussian blue deposited. While dry the impression is dove colour or lavender-blue, which has a curious and striking effect on the greenish-yellow ground of the paper, produced by the saline solution. After washing, the ground colour disappears, and the photograph becomes bright blue on a white ground. If too long exposed, it gets “over-sunned,” and the tint has a brownish or yellowish tendency, which however is removed in fixing; but no increase of intensity beyond a certain point is obtained by continuance of exposure.
– Sir J. F. W. Herschel, On the Action of the
Rays of the Solar Spectrum on Vegetable Colours,
and on some new Photographic Processes

If, for instance, you were ordered to paint a particular shade of blue called “Prussian Blue,” you might have to use a table to lead you from the word “Prussian Blue,” to a sample of the color, which would serve you as your copy. 
– Ludwig Wittgenstein, The Blue Book

What has the Food and Drug Administration (FDA) determined about Prussian blue?
The FDA has determined that the 500 mg Prussian blue capsules […] can be found safe and effective for the treatment of known or suspected internal contamination with radioactive cesium, radioactive thallium, or non-radioactive thallium.

How does Prussian blue work?
Prussian blue works using a mechanism known as ion exchange. Cesium or thallium that have been absorbed into the body are removed by the liver and passed into the intestine and are then re-absorbed into the body (entero-hepatic circulation). Prussian blue works by trapping thallium and cesium in the intestine, so that they can be passed out of the body in the stool rather than be re-absorbed. If persons are exposed to radioactive cesium, radioactive thallium, or non-radioactive thallium, taking Prussian blue may reduce the risk of death and major illness from radiation or poisoning.
– FDA/Center for Drug Evaluation and Research,
“Questions and Answers on Prussian Blue”

People may have blue feces (stool) during the time that they are taking Prussian blue.
– Centers for Disease Control and Prevention,
fact sheet on Prussian blue

Finally, essayist Cohen notes, “Tragically, “Prussian Blue” was the first Crayola-brand crayon to be renamed by the company — becoming “Midnight Blue,” in 1958. This change was prompted by American schoolteachers who found that their students were unfamiliar with the history of Prussia.”

-Julie

http://www.unrealnature.com/